You Can Win the War Against Mosquitoes in Bromeliads

Advice from Selby Gardens’ horticulture director on eradicating the pesky mosquitoes that live in the tropical plants.

On the cusp of rainy season, everybody’s Zika-wary, and rightly so. But Selby Gardens horticulture director Mike McLaughlin says don’t rip out those colorful tropical bromeliads that beautify your landscape. The mosquitoes that infamously breed in them are easily dealt with.

“We don’t want bromeliads to be vilified,” he says. “You don’t need to throw them out.”

Most bromeliads have “tanks” at their center that collect rainwater. (Tillandsias do not.) “In their natural habitat, they’re a source of water and a breeding ground for a host of animals,” says McLaughlin—frogs and many insect species. In the landscape it’s probably less so. “For us,” he says, “it’s trouble-free landscape that multiplies like a rabbit.” Bromeliad fans completely understand.

Selby Gardens, with one of the world’s great bromeliad collections (some 3,500 of them at last count), treats its bromeliads monthly without fail with a bacterium that comes in granular form. The bacterium doesn’t kill adult mosquitoes; rather, it kills their larvae. They use a brand called BTi, but other brands also are available at hardware stores and garden centers. A few granules per plant once a month—“more is not better,” he says—is “a nice, nontoxic way to deal with it.”

“What’s nice is it has a very specific target, and it doesn’t seem to affect other things like a pesticide would,” says McLaughlin. “It’s safe to use in ponds and around people and pets.” You do have to use it monthly to be effective. “This is a maintenance program, not a one-time deal and go.”

Of course, if you have three bromeliads on your fifth-floor condo patio, you can just flush them out with water regularly, and mosquitoes won’t be able to get established, McLaughlin says. “If you have a yard full of them, that’s not practical.”

Selby Gardens also employs tiny native mosquito fish that eat mosquito larvae in its Children’s Rainforest Garden water feature and in its koi pond. And McLaughlin advises everyone to look for other things in your yard that hold water—plant saucers, debris, fountains, etc.